When firing conventional weapon cartridges, the propellant charge within the cartridge is ignited, and the resultant propellant gas pressure propels (launches) the projectile from the cartridge. Generally, the propellant gas pressure is released with great force and high velocity, thereby causing a distinct and recognizable muzzle blast to be emitted from the weapon barrel. In addition, the rapid release of the high pressure propellant gases cause the projectile to be launched from the weapon barrel at a supersonic velocity, i.e., at a velocity greater than the speed of sound. A sonic boom is created upon reaching supersonic velocity, resulting in a distinctive noise signature.
Thus, firing of conventional weapon cartridges results in easily recognizable firing signatures, including muzzle blast and firing noise signature. In many situations, such as general combat, law enforcement, hunting, etc., such firing signatures are acceptable. However, in certain situations, these conventional firing signatures are undesirable and/or unacceptable. For example, special forces and sniper operations routinely require stealth and surprise. To maintain stealth and surprise, it is undesirable to create firing signatures, as they forecast to the enemy the location of the weapon.
Accordingly, it is an object of the present invention to provide a weapon cartridge having reduced or non-existent firing signatures upon firing, including reduced and/or eliminated muzzle blast and noise signature. In particular, it is an object of the present invention to provide a weapon cartridge that prevents rapid release of propellant gases from the cartridge upon firing (to minimize or eliminate identifiable muzzle blast), and is able to accurately fire the projectile at subsonic velocities (to minimize or reduce the noise signature created when the projectile reaches supersonic velocities).